1. Field
This invention relates to water injection apparatus for internal combustion engines. More particularly, it relates to a fluid injection system for injection of variable air and water mixtures into the manifold of an internal combustion engine in response to the intake pressures created therein.
2. State of the Art
Various fluid injection systems to inject water into an internal combustion engine to improve combustion are known. These water injection systems have become more popular in response to environmental concerns to reduce air emissions of unburned by-products. Peace et al., U.S. Pat. No. 4,391,230, illustrates a water injection apparatus for internal combustion engines mounted on the air fuel manifold of the engine. The Peace device utilizes a conduit system to provide a continuous flow of fluid mixture into the manifold, a second conduit connecting to the main conduit to inject a continuous flow into the carburetor, and a third conduit connecting the crankcase to the first conduit to collect and recirculate unburned fuel mixtures for re-injection into the carburetor. This device requires adjustment of the pressures in the manifold, carburetor, and crankcase for efficient fluid injection, and is primarily directed to reduction of air emissions. Turner, U.S. Pat. No. 4,391,229, discloses a steam injection apparatus heating a flow of fluid to produce steam via a coil associated with the exhaust system of a vehicle before injecting the same into the carburetor. This device requires extensive adjustments when ambient temperatures fluctuate, and the engine is not warm. In the field tests conducted by applicant, the Turner system left large beads of fluids in the lines when the engine is shut off. These fluids freeze, or are drawn into the engine in spurts upon re-start of the engine which causes erratic rough operations until the engine vacuum has cleared the air pockets in the lines. The Turner system vacuum is structured to directly pull water, but does not include a water regulator. Hence the fluid injection fluctuates as the water pick up varies when the level of the fluid in the holding tank goes down. After the vacuum to the engine has been shut off, the air valve regulating the fluid feed rate into the heating coils also has to be continually adjusted. The Turner device proportionates adjusts both the air and water inflows for admixture from both intake ports as the engine vacuum increases. It thus fails to provide an increasingly fluid enriched air mixture for injection into the intake manifold as the vacuum created by the engine operation increases.
The Turner air inlet is not restricted to allow a fixed flow of air through its valve to increase the liquid/air ratio of injected mist. Instead, the Turner device allows both the air and fluid flows to proportionally increase to provide a constant air/fluid mixture for injection into the engine until the line flow capacity of either the air or fluid lines is exceeded. Then, either the air or fluid flows will disproportionately increase in response to the increasing engine vacuum causing either a richer or leaner mixture to be injected. Without continuous adjustment of the both valves, wide fluctuations of the air/fluid mixture may result. For example, after initial setting, the air/fluid mixture is constant until line flow capacities of either the air or fluid lines is exceeded. At the point where either the line capacity of the fluid or the air lines is exceeded, different air fluid mixtures result. This irregular fluctuation of the Turner air/fluid mixtures creates highly inefficient combustion. Turner thus fails to provide an increasingly rich air/fluid mixture for injection into the intake manifold as the vacuum created by the engine operation increases. Consequently, the Turner device requires varying combustions of both the air and water valve intake adjustments over the operating range of the engine to insure optimal combustion performance. This continuous valve adjustment procedure is difficult when operating an internal combustion engine under operating conditions. Most vehicles do not allow continuous adjustment while operating.
Hart, U.S. Pat. No. 4,141,323, discloses another device utilizing a heater to inject a heated water vapor mixture into the carburetor for more efficient burning. Hart also suffers from the Turner starting problems as extreme ambient temperatures are encountered. Hart, U.S. Pat. No. 4,208,989 discloses another variation to produce heated air which is passed through a water filled container to produce vaporized water for injection into the carburetor. This moisture laden air has a tendency to precipitate in the lines when cold temperatures are encountered. Inamura, U.S. Pat. No. 4,125,092 discloses another device to inject a heated air water mixture at a point below the throttle and no later than the point the air fuel mixture enters the intake manifold. It requires a sophisticated timing system in response to the engine RPM's, which injects an air/water mixture when the engine is accelerating. Csonka et al., U.S. Pat. No. 4,279,223, discloses an internal combustion engine fuel saving and pollution reduction system. The device utilizes a recirculating system to collect condensed water from the exhaust gas of an engine, and re-circulates the same for injection into the carburetor. Means are required to control the amount of water passing into the engine. Temperature fluctuations of the ambient air materially affect the condensate characteristics of the exhaust gas, making cold starts difficult to regulate and control. Goodman, U.S. Pat. No. 4,191,134 discloses a fluid injection system and method for an internal combustion engine to inject a finely divided spray of fluid into the engine in response to both the engine speed and the exhaust gas pressure. This device requires careful regulation of the engine intake and exhaust pressures via an air injection pump system.
Hubbard, U.S. Pat. No. 4,800,848 discloses a water injection apparatus for Internal Combustion Engine which injects water mixtures into the manifold of an internal combustion engine in response to the intake pressures created therein. The device cannot simultaneously adjust both the water to air ratios to enable an engine to used with different fuel mixtures.
None of these devices provides a simple device to provide fluid injection of various air/water mixtures directly into the intake manifold of an internal combustion engine in response to the vacuum created therein.